The function of the residual current circuit breaker is to protect electrical appliances and person’s life from the electric shock. The moving contact is a part of the residual current circuit breaker. Its function is to cut the current in the line in case of a fault occurring in the circuit. The leaf spring is the key element of the moving contact, because it, besides moving of the contact, it also influences on the electrical resistance between the fixed and moving contact and consequently on the heating of the entire residual current circuit breaker while operating. In this assignment, we first measured electrical resistance, the contact forces and thermovision on five different springs. According to the measured values, we made a numerical 3D-model in a Comsol Multiphysics program, carry out the simulations and compared the results to the measured values. In the end, we carry out the measurements on the updated contact system and compare it to the previous one. We have found out, that the contact force has a strong influence on heat generation and that the results of the numerical simulation are comparable to the measurements of the samples.
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